In contrast, the atypical vesicular glutamate transporter VGLUT3 was often co-expressed (Figures 1C and S6A) with cholinergic and monoaminergic neurotransmitters and more rarely alone or with the other VGLUTs or GABA. This supports the notion that VGLUT3 plays a distinct role in cell types that release non-canonical neurotransmitters. Acetylcholine occurred with most other neurotransmitters, whereas, for example, serotonin occurred only alone or with VGLUT3 or GABA. The gaseous neurotransmitter nitric oxide (i.e., Nos1 expression) was detected throughout the nervous system and did not combine preferentially with (or avoid) any other neurotransmitter (Figures 1C and S6A).
